The specific aims of this collaborative projecxt are to apply the new methods described in this aplication to obtain more accurate estimated of the population parameters of both minimal models and thus of both glucose disposal and beta-cell function in norma, obese and mominsulin-dependetn (NIDDM) subjects. Besides providing the population parameters and covariance matrix, these analyses will also permit us to indlude the covariates. For example, obesity is importnat in understanding the relation between glucose disposal and insulin secretion parameters and anthropometric variables, e.g. visceral adiposity (measured by TAC). In NIDDM, a major issue is to understand the integrated relation between glucose disposal and insulin secretion parameters in the light of other crucial variables such as blood pressure, triglyceride and FFA levels of visceral. These covariates will be included in the population analyses, and will help in our understanding of macrovascular/microvascular complita tions.